Write the structure of the monomers used for getting the following polymers:
(i) Dacron
(ii) Melamine-formaldehyde polymer
(iii) Buna-N

Explanation

To solve the question of identifying the monomers used to obtain the specified polymers, we will break down each polymer and its corresponding monomers step by step.

### Step 1: Identify the monomers for Dacron (Terylene)
Dacron, also known as Terylene, is a polyester. The monomers used to synthesize Dacron are:
- **Ethylene Glycol**: The structure of ethylene glycol is:
\[ \text{HO-CH}_2\text{-CH}_2\text{-OH} \]
...